Based on genetic analysis, Luo et al. (2004) identified P. t. corbetti as the likely ancestral Tiger population, with the radiation into other subspecies taking place 72,000–108,000 years ago. Of all the Tiger subspecies, P. t. corbetti showed the highest genetic diversity in microsatellite alleles, indicating a fairly stable evolutionary history, and alleles found in other subspecies were almost always a subset of those found in P. t. corbetti. Luo et al. (2004) also include all tigers in Myanmar and southwestern China as P. t. corbetti, unlike some previous authorities which considered some populations to belong to P. t. tigris.

Panthera tigris corbetti occurs in Myanmar, Thailand, Lao PDR, Viet Nam, Cambodia and southwestern China (Luo et al. 2004). Its status is poorly known compared to other Tiger subspecies, but the extent of its recent decline is serious, approaching the threshold for Critically Endangered. As recently as the 1980s-1990s, tigers were considered widespread in the region, though little studied (Dinerstein et al. 1997, Seidensticker et al. 1999). Now, however, “vast areas of Southeast Asia [were] recently found to be void of tigers and depleted of prey by hunters” (Walston et al. 2010a: 5). There is no evidence of breeding tigers in Cambodia or Viet Nam (Walston et al 2010b); Myanmar has only one population of potential viability (Hukaung Valley Wildlife Sanctuary) (Walston et al. 2010a), and Laos just a single confirmed tiger population of less than 20 mature individuals. According to government estimates of national tiger populations, the subspecies population is 352: Thailand (200), Myanmar (85), Viet Nam (20), Cambodia (20) and Laos (17) (GTRP 2010). There are few recent records from China (Yunnan province and Medog county, Tibet), where tigers may not be resident and are dependent on trans-boundary conservation areas with India and Myanmar (Kang et al. 2010). However, these national estimates are still speculative to some extent, and the number of tigers in confirmed, protected populations in these countries is substantially lower, a total of 202: Thailand (185, with 154 in the Huai Kha Khaeng complex and 31 in the Kaeng Krachan complex: Walston et al. 2010a) and Laos (17 in the Nam Et-Phou Louey National Protected Area: GTRP 2010). In Cambodia, there have only been a handful of confirmed tiger records since 2005, despite intensive survey efforts (Walston et al. 2010a). In Vietnam, tigers have not been photographed by camera trap since 1997 (Walston et al. 2010a). In Myanmar’s Hukaung Valley, the world’s largest tiger reserve, camera trap surveys identified only six individual tigers, with the paucity of data leading to a wide estimate of 7–71 adult and sub-adult tigers, with the authors concluding that numbers “are likely depressed due to intense hunting of both prey and tigers” (Lynam et al. 2009). The subspecies was assessed as Endangered in 2007, with a population well below 2,500, no single subpopulation larger than 250, and a continuing decline. It appears to be approaching the thresholds for Critically Endangered and a full assessment to see it it indeed meets these criteria will be undertaken for the next Red List update.

Dinerstein, E., Wikramanayake, E. D., Robinson, J., Karanth, U., Rabinowitz, A., Olson, D., Mathew, T., Hedao, P., Connor, P., Hemley, G. and Bolze, D. 1997. A Framework for Identifying High Priority Areas and Actions for the Conservation of Tigers in the Wild. A Framework for Identifying High Priority Areas and Actions for the Conservation of Tigers in the Wild.